• Anatomical structures are capable to determine sex in human identification. • Paranasal sinuses, in particular the maxillary sinus, is used for sex determination. • Cone bean computed tomography is considered as a new method in forensics. To evaluate whether the maxillary sinus (MS) may be used to determinate sex and age in a Brazilian population when using CBCT images. The CBCT scans of 420 individuals (228 females and 192 males) were retrospectively selected and linear measurements (height, width, length, inter-sinuses distance and maximum distance between sinuses) and volume calculation of both MS were performed. The sample was divided into two age groups: 18–40 years and >40 years. All data were submitted to descriptive (independent Student t test) and discriminant functional analysis to validate the expression of sexual dimorphism and age prediction in the metric parameters ( p < 0.05). All MS measurements were higher in males ( p < 0.001). No differences were found between right and left sides ( p > 0.05). The height of the right MS was the best individual sex discriminator (66.9%). When all parameters were combined, the overall accuracy rate of sex determination was 73.6%. For age, the youngest group showed higher measurements for height of both sinuses, left MS length and MS volume bilaterally ( p < 0.05). Only for inter-sinuses distance the values for the younger group were lower ( p < 0.001). This parameter was the best individual discriminator (63.1%), and when all parameters were combined, the overall accuracy rate of age determination was 67.6%. Measurements of MS in CBCT images can be applied in a complementary way in the identification of sex. For age prediction, the use of MS is less accurate.